The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 25, 1995
Filed:
Feb. 11, 1993
Turuvekere R Gururaja, North Andover, MA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A transducer for transmitting and receiving ultrasonic energy at more than one frequency includes first and second electrostrictive layers mechanically coupled together such that ultrasonic vibrations in one layer are coupled into the other layer. The first electrostrictive layer is laminated between upper and middle electrical contact layers, and the second electrostrictive layer is laminated between middle and lower electrical contact layers. A bias voltage arrangement selectively produces within the first and second electrostrictive layers electric fields oriented in opposite directions or electric fields oriented in the same direction. When the electric fields are oriented in opposite directions, the transducer has a first resonance frequency. When the electric fields are oriented in the same direction, the transducer has a second resonance frequency. By selecting the number of electrostrictive layers in a transducer and by selecting the thicknesses of different layers, a transducer having two or more different desired resonance frequencies may be produced.